This invention relates to flow control and more particularly, to the directional control cf fluid flow and injected fluids.
It often is desirable to control the flow of fluid such as liquids and gases. A common device for that purpose is known as a check valve. It functions by the deflection of an elastomeric element towards and away from a valve seat. The deflection is towards the valve seat in order to prevent flow, and away from the seat to permit flow.
In some cases the control of fluid flow is with respect to a multiplicity of channels that have varying degrees of convergence with one another. A typical multichannel arrangement makes use of connectors which permit the intercoupling of flow channels as desired. For example, when two channels are to be joined selectively to permit a common output from a single channel, the connector can take the form of a fitting that resembles a "Y".
The inclusion of control valves in the various lines leading to a coupler can pose a number of complications. The inclusion of separate control elements can cause difficulties in assuring proper sealing. A common point of leakage in a line often occurs where the line has been severed in order to receive a control element. In addition, the inclusion of separate control elements in various lines leading to a coupler does not always provide the most efficient control over fluid flow.
One solution for overcoming difficulties associated with prior art valves that control flow on multiple channels is set forth in U.S. Pat. No. 4,610,276 which issued Sept. 9, 1986. This patent discloses a directional flow control valve with a main channel for the through-flow of fluid and a branch channel connected to the main channel at an intermediate position. This permits the convergence of flow through the main channel with flow through the branch channel. At the convergence of the two channels, there is a diaphragm for controlling the flow between the two channels. The diaphragm is clamped and bowed under pressure into the inlet of the branch channel. The application of pressure to the diaphragm assures the sealing of the branch channel against flow diverted from the main channel.
There also is a common housing in the '276 patent for the main flow channel and the branch flow channel. The diaphragm is bowed into the branch channel by a set of prongs with tips that extend as projections from a shelf that is common to the branch and main channels. The bowing of the diaphragm is asymmetric, and greater pressure is applied away from the region of outflow from the branch channel.
While the diaphragm of the 4,610,276 patent operates properly in most cases, there is the possibility that the diaphragm will fail to seat properly.
Another valve arrangement for dealing with main and branch channels is disclosed in U.S. Pat. No. 4,874,369 which issued Oct. 17, 1989. This arrangement employs an injection site in conjunction with a valve, illustratively of the duck-bill type, in a configuration that is complex, costly and difficult to manufacture. In addition, duck-bill valves of the type contemplated by the '369 patent have proved to be unreliable in practice, with such difficulties as failure to seal properly.
Other arrangements which relate to the control of fluid flow are disclosed in Osborne U.S. Pat. No. 2,270,468; Goott et al U.S. Pat. No. 3,370,305; Craft U.S. Pat. No. 3,457,933; Rosenberg 3,572,375, 3,650,093 and 3,710,942; Melnick U.S. Pat. No. 3,891,000; Mittleman U.S. Pat. No. 4,000,740 and 4,405,316; Stevens 4,000,739; Zedes et al U.S. Pat. No. 4,005,710; Mittleman et al 4,048,996 and 4,133,441; Rushkie et al U.S. Pat. No. 4,222,407; Sheehan et al 4,294,249; Spademan 4,338,934; Spector et al 4,424,833; Edwards et al 4,566,493 and Suzuki et al 4,610,674; EPO 0109903; France 2004771 and UK 2033230. None of these arragements provide enhanced flow control where there is diversion of fluid flow from one direction to another.
Accordingly, it is an object of the invention to enhance the control that can be achieved over fluid. A related object is to enhance flow control where there is a diversion of fluid flow from one direction to another.
A further object is to achieve greater reliability over valve operation than is achievable by clamped diaphragm and duck-bill valves.
Still another object is to achieve precision control at reduced cost and simplification.
A further object of the invention is to improve the performance of injection site valves.